Include short package description in help string for configure --enable-SPKG, improve formatting

Author: Matthias Koeppe

bootstrap

@@ -97,7 +97,7 @@ AC_SUBST(SAGE_ENABLE_$pkgname, [yes])"
                         _*) ;;
                         *)  spkg_configures="$spkg_configures
 AC_SUBST(SAGE_ENABLE_$pkgname, [if_installed])
-SAGE_SPKG_ENABLE([$pkgname], [$pkgtype])" ;;
+SAGE_SPKG_ENABLE([$pkgname], [$pkgtype], [$(head -n1 build/pkgs/$pkgname/SPKG.rst 2>/dev/null || echo $pkgname)])" ;;
                     esac
                 fi
     done

m4/sage_spkg_configure.m4

@@ -63,7 +63,7 @@ echo "Checking whether SageMath should install SPKG $1..." >& AS_MESSAGE_FD
 AS_BOX([Checking whether SageMath should install SPKG $1...]) >& AS_MESSAGE_LOG_FD
 
 AC_ARG_WITH([system-]SPKG_NAME,
-       AS_HELP_STRING(--with-system-SPKG_NAME={no|yes (default)|force (exit with an error if no usable version is found)},
+       AS_HELP_STRING(--with-system-SPKG_NAME={no|yes⁽ᵈᵉᶠᵃᵘˡᵗ⁾|force (error if no usable version is found)},
            [detect and use an existing system SPKG_NAME]),
        [AS_VAR_SET(SPKG_USE_SYSTEM, [$withval])],
        [AS_VAR_SET(SPKG_USE_SYSTEM, [yes])]

m4/sage_spkg_enable.m4

@@ -1,22 +1,22 @@
 AC_DEFUN([SAGE_SPKG_ENABLE], [dnl
   m4_pushdef([SPKG_NAME], [$1])dnl
   m4_pushdef([SPKG_TYPE], [$2])dnl
-  m4_if(SPKG_TYPE, [standard], [
+  m4_if(SPKG_TYPE, [standard], [dnl
     dnl standard packages; help message is deliberately very brief,
     dnl as this is for advanced users only
     AC_ARG_ENABLE(SPKG_NAME,
       AS_HELP_STRING([--disable-]SPKG_NAME,
                      [disable $2 package ]SPKG_NAME),
       AS_VAR_SET([SAGE_ENABLE_]SPKG_NAME, [$enableval])
     )
-  ], [
+  ], [dnl
     dnl optional/experimental packages
     AC_ARG_ENABLE(SPKG_NAME,
-      AS_HELP_STRING([--enable-]SPKG_NAME={no|if_installed|yes},
-                     [enable build and use of the $2 package ]SPKG_NAME[ (default: "if_installed")])
-AS_HELP_STRING([], [package information: ./sage -info ]SPKG_NAME)
+      AS_HELP_STRING([--enable-]SPKG_NAME={no|if_installed⁽ᵈᵉᶠᵃᵘˡᵗ⁾|yes},
+                     [enable build and use of the SPKG_TYPE package $3], [26], [100])
+AS_HELP_STRING([], [package info: ./sage -info SPKG_NAME])
 AS_HELP_STRING([--disable-]SPKG_NAME,
-                     [disable build and uninstall if previously installed by Sage in PREFIX; same as --enable-]SPKG_NAME[=no]),
+                     [disable build and uninstall if previously installed by Sage in PREFIX; same as --enable-]SPKG_NAME[=no], [26], [100]),
       AS_VAR_SET([SAGE_ENABLE_]SPKG_NAME, [$enableval])
     )
   ])dnl